U.S. Pat. No. 3,504,510, issued Apr. 7, 1970 to Daniel Freze, et al. discloses a drum having an effluent duct at the rear and opposite the loading door. A baffle plate hopefully keeps the work away so that the effluent duct remains open during the exhaust cycle. In practice, an operator must continually inspect the drum to stop the drum and pull the work away. U.S. Pat. No. 3,381,507 issued May 7, 1968 to Harold C. Burgo et al. discloses a drum provided with peripheral openings. With the work always falling to the bottom, the openings on top cannot be clogged. Hence a good uninterrupted flow of air is ensured. However, Burgo's machine requires an axially movable wall to expose the apertured drum part at one end to the unapertured drum part at the other only during the purging part of the operation so that the cleaning agent isn't lost during the cleaning part of the cycle. The Freze machine has the advantage that the drum is unchanged during both parts of the cycle and consequently requires no mechanisms that must be serviced. The Burgo machine makes possible a very certain and effective purging of used cleaning agent.
The primary object of this invention is to provide an improvided cleaning machine of this character that utilizes peripheral effluent openings without requiring any moving mechanisms to retain the cleaning agent in the drum during the cleaning part of the cycle. Accordingly high volume purging air flow is achieved without any possibility of the work clogging the effluent openings.